1. Field of the Invention
The present invention relates generally to a bearing pulley structure, and more particularly to a ratchet pulley.
2. Description of the Related Art
The conventional bearing pulley used on a sailboat includes a pulley and a connection section such as a shackle. A rope is wound over the pulley. The connection section is used to support the mast, yard or deck of the sailboat. On the demand of sailing control, the bearing pulleys respectively installed in different positions are required to have work-saving devices with ratchet function.
A common bearing pulley can be rotated left and right (counterclockwise and clockwise). An improved bearing pulley has been developed, which has a selection switch for switching the bearing pulley between two modes. One of the modes is to left and right rotate the bearing pulley, while the other of the modes is to one-way rotate the bearing pulley.
There is another type of bearing pulley in which when the rope is pulled and the pulley is loaded, the rotational direction of the pulley is limited.
Accordingly, there are two kinds of bearing pulleys arranged in different positions in accordance with different requirements.
Furthermore, there is a three-in-one bearing pulley with the above three functions. Such bearing pulley has two selection switches. One of the switches is used to select whether the bearing pulley is left and right rotatable or one-way rotatable. The other of the switches is used to select that the rotational direction of the pulley is limited when the rope is pulled and the pulley is loaded. Such bearing pulley is advantageous in that it can be freely installed in any desired position. However, such bearing pulley has a larger size. In other words, it is impossible for a small-size bearing pulley to have two switches. Moreover, it is still inconvenient to use the bearing pulley with two selection switches.